The head of South Korea’s army resigned Tuesday over a property investment as tensions on the Korean Peninsula were high after a deadly North Korean artillery attack on a South Korean island last month.Hwang Eui Don, 56, had held the post of army chief of staff for six months before submitting a request to President Lee Myung Bak for an early retirement. Lee accepted it, the Yonhap News Agency reported.Hwang had been criticised for a substantial profit he made on a property investment in Seoul after allegedly receiving information beforehand from officials that building regulations would be loosened, South Korean media said.Hwang denied the allegations, but a defence ministry official cited by Yonhap said, “General Hwang offered to retire following media reports about his property investment because he judged it was inappropriate for him to stay on the post at a time when he has to lead the reform of the army.”He resigned as the military is on high alert after the Nov 23 artillery attack on Yeonpyeong island near the two Koreas’ disputed maritime border in the Yellow Sea. Four South Koreans were killed.Then-defence minister Kim Tae Young resigned two days later amid criticism that South Korea’s reaction to the attack was too slow and too lax. Former chairman of the Joint Chiefs of Staff Kim Kwan Jin replaced him.S Korea suspects North has more uranium sitesSouth Korea believes that the North has been secretly enriching uranium at new locations outside its main nuclear site, the country’s foreign minister said Friday, declining to say how many sites there were.Earlier, a South Korean newspaper cited an unnamed intelligence official as saying that the North was enriching uranium at three or four sites in addition to its main nuclear site in Yongbyon.“It is a report based on what is still intelligence and let me just say that we have been following this issue for some time,” Foreign Minister Kim Sung-hwan told a press briefing on Tuesday when asked about it.Kim reiterated South Korean demands that China, the reclusive North’s backer, exercise greater influence on its ally “with a clearer voice.”Uranium enrichment could give the North a second source of fissile material for weapons on top of its plutonium production program at the Soviet-era nuclear program at Yongbyon, which was frozen under a now-defunct international disarmament deal.The report of additional uranium enrichment facilities came after Russian Foreign Minister Sergei Lavrov chided North Korea over its nuclear program and condemned an artillery attack on a South Korean island that killed four people last month.Concern over the scope of North Korea’s nuclear program grew after U.S. nuclear expert Siegfried Hecker toured the Yongbyon site in November, where he saw hundreds of centrifuges and was said to have been “stunned” by the sophistication of the program.Later that month, North Korea launched an artillery barrage against a South Korean island in what Pyongyang says are disputed waters, triggering concern about a potential conflict that could draw in the United States and China.